Automatic slack-adjuster.



fs. MARCQ. AUTOMATIC SLAGK ADJUSTER.

- APPLIATION FILED DEO, 2. 1909.`

968,371 Patented Aug. 23, 1910.

STEPHEN MAB-C0, 0F 4SAN FRANCISCO, CALIFORNIA.

AUTOMATIC SLACK-ADJ'USTER.

Application filed December 2, i999, Serial'No. 530,965.

'1o aLL w/Lom t may concerm' y', j

-Be it known that I, STEPHEN MARCO, a c1tizen of the United States, residing at the city and county of San Francisco and State of California, have invented new and useful Improvements in Automatic Slack-Adjusters for Car-Brakes, of which the .followin 'is a specification. j

his invention relates to automatic slack.- adjusters for car brakes.

It is the object. of this invention to provide a brake slack adjuster which embodies means by -whichI the length of thebrake rod or rods will be automatically adjusted so as to compensate for the wearingA of the brake-shoes, or otheroccurrences, which will make such adjustment necessary.

The invention consists of the parts, and the combination and construction of parts as hereinafter more fully described and claimed, reference beinghad to the laccompanying drawings, in Whichj Figure 1 is a plan view of the invention as applied. Fig. EZ is a longitudinal section of the adjuster. F 3 is a cross section on the line m-w Fig. 2. Fig. 4: is a cross section on the line yy Fig. 2.

In the drawings I have illustrated the invention as applied to a combinedY air-brake and hand-brake mechanism, but it is mani-- fest that the device is applicable to carbrake mechanism of either the hand-brake,

or air-brake variety; and is especially suitable Where a brake cylinder is employed.'`

The stroke ot' the piston in brake cylinders is limited, and should the brake shoes becoineworn excessively, the piston might travel out until it struck the back' head before the shoes would contact the wheels,for that reason it is desirable to keep the travel of the brake cylinder piston as uniform as possible, which in most cases is about 8' inches. If the travel of the piston be less than the prescribed stroke,ithe shoes are apt to stand too near the Wheels, while if greater than this, a small amount of eXtra wear of the shoes would allow the piston to strike the head, therefore I employ the following described invention for iautomatically taking up this slack.

A represents a brake cylinder of anysuity able type in which affiiston is adapted to be reeiprocated in the'usual manner. -The cylinder A is mounted on the underside of 5 a car, not necessary to`be here shown.

1'1 The piston .rod .2 is pivotally connected"L to one end of a floating lever 3, at 3. The.V

opposite end of leyer 3 is pivoted at 3 to a brake-rod 4, which leads to brake shoes, not shown, which are adapted to act upon the Wheels at the rear end of a car, andzmay be of vany suitable construction. A second lever or arm 5 is pivotedf at one end to a fixed support, in .this case shown as a yoke 5 on :the brake cylinder A.. The opposite end of this arm 5 is pivoted at 5 to a brake-rod 6,

extending in the opposite direction Ato the rod 4, and leading to brake shoes on the forward end of a car.

7 is a rod which connects the lever 3 and arm 5, one end ofthe rod 7 terminating in a yoke 7 which is pivoted to the'lioating lever 3, and the'other end mounted in my automatic slack adjuster C as later .de-

scribed, which is pivoted at 7av to thearni 5.

8 is a second rod, connecting the levers 3 and 5 in a similar manner as the rod 7, excepting that the yoke S connecting the rod 8 to the lever 3, isslotted at 9 so as to be movable upon a pin 1() fixed to the lever '3, thereby allowing a certain amount of' slack movement. A coil spring 11 surrounds ,therod 8, and bears between the yoke 8 and the slack adjuster C, which is constructed as shown in Fig. 2, in which C is the casing of the slack adjuster which may be of any suitable size and form, butishere shown as a cylindrical tubular shell, one end terminating in a yoke 12, which is adapted to be pivotally connected to the arm 5, as shown at 7L and 8a.

The yoke l2 is formed on a cap 13 which is threaded-into the shell C so to forni a tight closure. The other end of the shellv @terminates in a tapered end portion, i n tegral with the shell (l, which is provided with a bore 111-, through which the end of a rod, 7 or 8, may freely pass. The portion of the rod extending through the bore 14 into the interior ot' the casing C is threaded with vsquare threads 15, which engage with the to the revoluble spindle 19, and its outer end fastened to the tiXed head. 13.

In operation, referring to Fig. L1-when the end B of the iioating lever 3 is 'moved ias outward in the direction indicated by the arrow Z, by the application o power, the action will be to turn the lever about its tulcruni point T', and simultaneously -move the arm on its bearing at 5 so as to move the brake rods and (3, on the outer ends of the levers 25 and in the direction indicated by the arrows.

A certain. amount ot' movement will be allowed the lever 3 beiore the rod is eti'ected, by reason. of the slot `9. When .the pin 1t) contacts at theinner end ot the slot 9, pressure will be exerted upon the rod 8,

in opposition to the spring 11, which spring tends to exert a continuous" pull upon the rod S in relation to the slack adjuster (l.

. The operation of the slaclradjuster, referring to Fig. 2, is as follows: The connecting rods 7-8 are previously adjusted and set to the proper length, with the spring 20 wound upon the spindle'l.) under tension. The action of this spring 2O is to screw the nut 16 upon the threaded end of4 the connecting rod therein, when there is an excess of slack. r1`his excess of slack is denoted by the throw ot' the outer ends of the levers 3 and 5, which when the brake shoes are worn, would be greater' than otherwise. This increased bacluvard movement of the levers 3 and 5 causes`the pin 1 to press upon the bar 8, and cause it to move into the casing (l, whereupon the spring 20 will screw the nut 16 upon the bar 8 the length of the slack, thereby shortening the rod 8 that amount, so that the brake shoes will be held a proper distance from the wheels. When the levers 3 and 5 return to their normal position, the spring 11 exerts suiicient pull upon the bar8 to bind the threads 15 in the nut 16, thereby'` prevent-- ing the latter being rotated by the spring 20. '1`he adjuster on the bar 7 is operated in a similar manner as that on the barv 8, to shorten the bar 7 inl proportion to the shortening of the bar 8, a nut 16 screwing upon the bar 7, when the latter is relieved of strain by the pin 10 pressing upon the outer end of the slot 9.

Perforations 21l are formed vin the periphery ot' the nut 16, so that it may be rotated to wind the spring 20, and at the saine time unscrew from the rod therein, thereby iii- 'creasi-ng the connecting length of the rod,

when desired.

A slot 22 is formed in the shell C through which any suitable tool may be inserted to engage the nut 16, a cover 22 being pro# vided which is adapted to close the slot 22,

as shown in Fig. 3.

I have. shown in'Fig. 1, the lever 3 connected to the rocking-bar 23 ot' a handbralie, not shown, -by a chain 24:. The handbrale may be constructed in any suitable manner, as the operation of the slackadjuster is not dependent on any particular form of brake construction otherthan that described.

No means are shown for returning the levers 3 and 5 to their normal position, as

that is accomplished by 'means of springs on the brake slices, or iii-any other manner common in car brake construction.

Ii the take lup mechanism is located contiguous to the fulcrum ofthe pivoted lever, there will not be a sutlicient space to take up tor brake shoe wear, and the position of the lever will be so changed with relation to the lioating lever that it will become measurably detective in action.

Y In my invention, the distan justing device is such that a very considerable wear and corresponding adjustment may take place without any such results.

Having thus described my invention, what I claim and desire to secure by Letters Patent isy 1.' The combination with an air' brake cylinder, fixed and floating levers, and brake connecting the levers lbetween their, ends, said rod having screw-threads at one end, a casing, a contained nut in which the, threaded end of the rod is turnable, means to turn the nut within the casing, means normally acting to hold the nut against turning, and means actuated by one of said levers for relaxing the holding means and thereby permitting the nutto be turned.

2. 'lilie combination with an air brake cylinder, fixed and floating levers, and brake rod connections with said levers, of a rod connecting the levers between their ends, said rod having screw-threads at one end, a. casing, a contained nut in which the threaded end' of the rod is turnable, means to turn the nut within the casing, said means consistingof a coil-spring within the casing vrod eonnectionswith said levers, of a rod and `a connection between one end 'of the spring and the nut, means acting normally to hold the nut fromturning, and means -for relieving the holding means to allow said spring to turn the nut.

3. The combination with an air brake cylinder, fixed and floating levers, brake rod connections with said levers, of a rod con- -necting the levers between their ends, said rod having screw-threads at one end, a casing, a contained nut in which the threaded end of the rod is turnable, a coil spring within the casing having one end connected with the nut, and a spiral tension spring producing a trictional contact between the screw-threads of the nut and bar.

4. The combination with an air brake cylinder,',ixed and floating levers, brake rod connections with said levers, of 'a plurality of rods connecting the levers between their ends, said rods having screw-threads at one end, casings connected with one of the levers, nuts contained in the casings engaging the screw-threaded ends of the rods, coil springs connected to turn the nuts upon the rods, a

c turning, and and. relieve spiral spring acting normally to produce a rictional contact to prevent the nuts from means to compress the spring the friction to allow the coil spring to act.

5. The combination with an air brake cylinder, ixed and floating connections with said levers, of rods connecting the levers of a plurality connected to turn the nuts upon the rods, a

levers, brake rodbetween theirV ends, said rods having screwfthreads at one ,4

spiral normally compressed spring inclosing one of the rods, said rod having a slot, a pin fixed to the opposite lever and slidable in the slot, said pm Contactin 'with the bottom of the slot and relieving the rictonal contact of the screw-threads to allow the nut to turn and advance upon the rod to compensate for slack.

In testimony whereof I-have hereunto set my hand in the presence of two subscribing' witnesses.

STEPHEN MARCO.

WVitnesses:

CHARLES R. Hormon, JGHN R. BRIDE. 

